I made a test run today. I just welded a couple of pieces at a 45 from the front lip to the SSQA plate and decided to test it out before I spent too much time welding on it.
It works pretty good. The angle of it on the ground makes a big difference. If it is tipped forward at all it will plow down through the gravel and build up enough that it flows over the top and on to the plate. Seems to work best tipped back ever so slightly. I was hoping to use it in float mode but I think it will need some more weight added for that to work properly. I ran it with a little bit of down pressure and it did exactly what I wanted it to. There is a lot of friction going on at the bottom of the plate and I figured it would get warm but it gets hot! I only ran it 10-15 minutes and the bottom of the plate was so hot water would sizzle on it.
I am going to finish welding some more bracing on it and fill it with concrete and it will be my go to tool for smoothing the gravel.